Silvana E. Vignaduzzo

DEVELOPMENT AND VALIDATION OF AN HPLC METHOD FOR THE SIMULTANEOUS DETERMINATION OF AMLODIPINE, HYDROCHLOROTHIAZIDE, AND VALSARTAN IN TABLETS OF THEIR NOVEL TRIPLE COMBINATION AND BINARY PHARMACEUTICAL ASSOCIATIONS

The novel triple combination between Amlodipine (AML), Hydrochlorothiazide (HCT), and Valsartan (VAL) provides a new option for treating hypertension. The development and validation of an HPLC method for their simultaneous determination in pharmaceutical combinations, employing experimental design strategies, is reported. The drugs were separated on a C18 column at 30°C, using a 38:62 (v/v) mixture of 30 mM phosphate buffer (pH 5.5) and MeOH as mobile phase, delivered at 1.0 mL min−1. Detection was performed at 234 nm. Despite the wide difference in analytes’ concentrations, the method showed good linearity (r2 > 0.995) in the ranges 7.0–13.0 µg mL−1, 17.6–32.8 µg mL−1, and 226.2–420.2 µg mL−1 for AML, HCT, and VAL, respectively, being specific (peak purity >0.999), accurate (bias of analyte recoveries <2.0%), and precise (inter- and intra-day variations <2%). It was also robust to small changes in flow rate (±0.05 mL min−1), pH (±0.1 unit) and proportion of MeOH (±3%) in the mobile phase. The method was applied to the assay of AML, HCT, and VAL in tablets of their novel association and formulations containing the HCT-VAL and AML-VAL binary combinations.

EXPERIMENTALLY DESIGNED, VALIDATED HPLC SIMULTANEOUS DETERMINATION OF PRIDINOL AND DICLOFENAC IN THEIR COMBINED PHARMACEUTICAL FORMULATIONS, WHICH ALLOWS LIMITING DICLOFENAC RELATED COMPOUND A

The development and validation of an HPLC method for the determination of pridinol and diclofenac in their combined formulations and the simultaneous limit testing of diclofenac related compound A is described. The separation was performed on a C18 column. Experimental design and response surface strategies were employed for optimizing detection wavelength (225 nm) and mobile phase composition [MeOH:2-propanol:phosphate buffer (50 mM, pH 5.5), 48:9:43 (v/v/v), 1 mL min−1], and for validation purposes. The method was successfully applied to the quality control of commercial brands of tablets and capsules. Found impurity levels were below 0.1% (LOQ = 0.02%). Stressed samples were also evaluated.

DEVELOPMENT AND VALIDATION OF A HPLC METHOD FOR THE SIMULTANEOUS DETERMINATION OF BROMHEXINE, CHLORPHENIRAMINE, PARACETAMOL, AND PSEUDOEPHEDRINE IN THEIR COMBINED COLD MEDICINE FORMULATIONS

A simple and efficient liquid chromatographic method has been developed and validated for the simultaneous determination of bromhexine, chlorpheniramine, paracetamol, and pseudoephedrine in common cold medications (tablets and syrups). The separation of the analytes was achieved within 10 min, employing a mixture of 10 mM triethylamine-phosphoric acid buffer (pH 4.0) and MeOH (35:65, v/v) as isocratic mobile phase, pumped at 1.0 mL min−1 through a cyano column (5 µm particle size). The analytes were detected at 215 nm. Statistical experimental designs and graphic representations (response surface methodologies, Pareto charts) were used for selecting the proper detection wavelength, optimizing the mobile phase composition, and assessing method robustness. The linearity of the calibration (r > 0.99, n = 21) in the relevant ranges (up to 130% of the expected concentrations of the analytes in the formulations), method accuracy (bias < 2.0%), repeatability (RSD < 2.0%) and intermediate precision, were verified. In addition, specificity (peak purities with photodiode array detector >0.9997) and method robustness were evaluated, and system suitability parameters were determined. The validated method was successfully employed for the routine analysis of various commercial tablet and syrup pharmaceutical preparations against the common cold, showing satisfactory analyte recoveries and RSD values.

Development of a Dissolution Test for Fenbendazole-Praziquantel Capsules Using UV-PLS Method

A dissolution test for capsules containing 50 mg of praziquantel and 500 mg of fenbendazole was developed and validated. The optimal conditions were an USP apparatus 2 with paddles rotating at 75 rpm, 900 mL dissolution medium (a mixture of 300 mL of ethanol and 600 mL 0.5 mol L HCl), at 37.0 ± 0.5 °C. Both analytes achieved with sink conditions. A published highperformance liquid chromatography (HPLC) method was used to monitoring dissolution test during the optimization. Additionally, a chemometrics method based on UV-VIS spectrophotometry and partial least-squares (PLS) was developed and validated for the simultaneous determination of both analytes in the dissolution media. The coefficients of determination were 0.9986 and 0.9959 for fenbendazole and praziquantel, respectively, and the elliptical joint confidence region (EJRC) test concluded that constant and proportional biases were absent. The optimized model was applied to build dissolution profile and its results did not show statistical differences with HPLC method.